In seven days, Donald Trump will be the president of the United States.

The man who takes to Twitter in a flying rage when his vice-president is criticised by actors in a musical will be at the helm of the most powerful military in the world.

The man who has filed for bankruptcy six times will have critical influence on the US - and therefore the global - economy.

The man who has openly bragged about grabbing women "by the pussy" will set America's human rights agenda.

Anyone holding out hope that Mr Trump would, after the election, morph into a person ready to take on this awesome responsibility with the dignity and respect it deserves, will have been disavowed of that notion this week.

At a press conference on Wednesday, Mr Trump proved that the braggadocio, aggression and incoherence displayed in his presidential campaign was no act.

He is exactly what you would expect a casino mogul and television show host to be: entertaining, callow and surrounded by the whiff of scandal.

So strap in, ladies and gentlemen. The next four years are going to be a wild ride.

In part, the shock of the Trump presidency is aesthetic. After eight years of Barack Obama, possibly the best orator on the planet, Mr Trump's simplistic grasp of the English language grates all the more.

Where Mr Obama's addresses are a skilful, sensitive weave of the complexities of a problem, Mr Trump gravitates to schematic extremes.

At Wednesday's press conference, his first since winning the election, he presented himself, without irony, as the leader of "a movement like the world has never seen before".

He vented his fury at intelligence agencies that he accused of leaking unsubstantiated reports that Russia was in possession of compromising material about him by invoking Nazi Germany.

His discussion of the claims that Russia launched cyber attacks to interfere in the US election sounded like a disquisition on a football game: chastising the Democratic National Committee for not having sufficient "hacking defence".

But it's not just Mr Trump's inarticulate style that speaks to the drama of the coming years.

The dossier put together by a British former MI6 agent for an opposition research group - published by Buzzfeed this week - is raw intelligence, a collection of unfiltered and unverified accounts from contacts in the FSB, the successor to the KGB.

But if even one of the allegations laid out against Mr Trump in its 35 pages proves to be true, Watergate would pale in comparison to its consequences. There is reason to believe there is more to come out.

As one Washington insider pointed out to me, the leaders of the FBI, CIA and National Security Agency, tend to be at loggerheads, often briefing against one another as their agencies vie for power and influence.

For all three to agree, as they did last week, that the contents of the dossier were credible enough to attach a two-page summary to a classified report given to Mr Trump and Mr Obama, indicates they know more than has been admitted.

And some of the allegations have been repeated elsewhere.

In the summer of last year, I spoke to a former US intelligence source who told me that the Russians were in possession of a "kompromat" - blackmail videotape, showing Donald Trump with prostitutes in a Moscow hotel.

He knew this, he said, from communications that had been intercepted by a Eastern European intelligence agency.

The former agent also urged me to follow the money.

Not just the election, but Mr Trump's whole career, he claimed, is wrapped up in questionable financing from Russia.

"It's like every part of his business is somehow tied up in it," he said.

Much has been written about Bayrock, the property development firm that was building Trump SoHo, his towering building in New York and other projects.

A key principal in Bayrock was Felix Sater, a Russian convicted of helping to lead a massive mafia-linked Wall Street stock fraud scheme. (Mr Sater also attacked a man at a New York bar by stabbing him in the face with the broken stem of a Martini glass).

Two lawyers, Frederic Oberlander and Richard Lerner, who have spent much of their careers tracking Bayrock's dealings, allege in court documents that Bayrock "for most of its existence was substantially and covertly mob-owned and operated".

In a petition to the US Supreme Court, they write that Mr Sater's father, Michael Sheferofsky, worked for Semion Mogilevich, the Russian mafia boss allegedly described by the FBI as "the most dangerous mobster in the world".

The company was based in Trump Tower, and, despite Mr Trump's claims that he barely knows Mr Sater, there is much reporting to show the opposite.

David Johnston, an American journalist who has spent years looking into connections between Mr Trump and the mafia, wrote in 'Politico' during the election that no other candidate for the White House "has anything close to Trump's record of repeated social and business dealings with mobsters, swindlers, and other crooks".

Then there is the most serious claim in the dossier: that the Trump campaign had colluded with Russia, in Moscow's alleged efforts to intervene in the presidential election.

At the press conference, Cecilia Vega of ABC News gave Mr Trump the opportunity to put this explosive allegation to bed.

She asked: "Mr president-elect, can you stand here today, once and for all and say that no one connected to you or your campaign had any contact with Russia leading up to or during the presidential campaign?"